docs: design ASAPPlanner-aligned collector plan interface

[zzylol]

Summary

Redesign the ASAPQuery-backend control-plane → ASAPCollector interface around ASAPPlanner’s current post-ASAP definitions.

• keep ASAPPlanner responsible for candidate logical DAGs and summary semantics;
• place candidate selection, stage allocation, source binding, runtime windows, and transmission policy in the ASAPQuery-backend physical-planning layer;
• compile one selected DAG into matching CollectorPlan and BackendPlan portions;
• bind both portions with shared plan_id, plan_version, backend_compat, and materialization identities;
• define a versioned YAML CollectorPlan carried by OpAMP protobuf rather than serializing Planner’s Rust DAG;
• map SummaryAgg, SummaryFamilyType, typed algorithm parameters, Reduction, GroupingStrategy, and SummaryEstimate to runtime fields;
• distinguish Reduction::PerEntity from an empty global reduction and preserve shared multi-subpopulation/Hydra grouping choices;
• define source matchers, windows, placement, raw/full/delta transmission, validation, atomic activation, and fail-closed behavior;
• define semantic application reports in addition to OpAMP RemoteConfigStatus; and
• clearly separate the target contract from today’s complete-OTel-YAML/restart implementation.

This is the collector-side companion to ASAPQuery-backend PR #444’s compiled-plan collector/backend split design.

Validation

• git diff --check
• Compared against ASAPPlanner main post-ASAP SummaryExpr, SummaryFamilyType, SketchKind, AccuracyTarget, Reduction, and GroupingStrategy definitions.
• Compared against ASAPQuery-backend PR feat(asapedgeprocessor): accept per-metric sample_p in fused asap_edge + sample HLL/CMS #444’s compiled-plan and backend-plan designs.
• Documentation-only change.